Third-order nonlinear optical response and photoluminescence characterization of tellurite glasses with different alkali metal oxides as network modifiers

Studies of the third-order nonlinear optical properties in TeO(2)-MO-R(2)O glasses with three different alkali metal oxides R(2)O (R - Li, Na, K) as network modifiers and two network intermediates MO (M - Zn, Mg) are reported. The influence of such modifiers and intermediates on the nonlinear optical properties of these glasses was investigated using the standard Z-scan and the thermally managed Z-scan techniques under femtosecond pulse excitation at 800 nm. For different modifiers and intermediates, the nonlinear refraction indices n(2) of these glasses varied in the range 1.31-2.81 (x10(-15) cm(2)/W). It was found that n(2) increases as the ionic radius of both network modifiers and intermediates decreases. Furthermore, the measurements show that the contribution from thermo-optical effects to the nonlinear refraction index is negligible for all of the studied glass compositions. In addition, the effect of modifiers and intermediates in the formation of localized states in the vicinity of the optical bandgap was also studied through photoluminescence experiments. These experiments revealed the presence of two emission bands (red and blue) originating from these localized states that can be populated after optical excitation and subsequent relaxation

Enhancing Optical Up-Conversion Through Electrodynamic Coupling with Ancillary Chromophores

In lanthanide-based optical materials, control over the relevant operating characteristics–for example transmission wavelength, phase and quantum efficiency–is generally achieved through the modification of parameters such as dopant/host combination, chromophore concentration and lattice structure. An alternative avenue for the control of optical response is through the introduction of secondary, codoped chromophores. Here, such secondary centers act as mediators, commonly bridging the transfer of energy between primary absorbers of externally sourced optical input and other sites of frequency-converted emission. Utilizing theoretical models based on experimentally feasible, three-dimensional crystal lattice structures; a fully quantized theoretical framework provides insights into the locally modified mechanisms that can be implemented within such systems. This leads to a discussion of how such effects might be deployed to either enhance, or potentially diminish, the efficiency of frequency up-conversion

Red, Green, Blue And White Light Upconversion Emission In Yb \u3csup\u3e3+\u3c/sup\u3e/Tm\u3csup\u3e3+\u3c/sup\u3e/Ho\u3csup\u3e3+\u3c/sup\u3e Co-Doped Tellurite Glasses

Several Yb3+/Tm3+/Ho3+ co-doped transparent TeO2-ZnO-Na2O-Yb2O 3-Ho2O3-Tm2O3 glasses were prepared and luminescence properties were characterized. Simultaneous red, green and blue (RGB) emission were obtained after excitation at 970 nm. Colour emission was tuned from multicolour to white light with colour coordinate (0.32, 0.33) matching very well with the white reference (0.33, 0.33). Changes in colour emission were obtained by varying the intensity ratios between RGB bands that are strongly concentration dependent because of the interaction of co-dopants. The colour tunability, high quality of white light and high intensity of the emitted signal make these transparent glasses excellent candidates for applications in solid-state lighting. © 2011 IOP Publishing Ltd

Strong green upconversion emission in Zr O2: Yb3+ - Ho3+ nanocrystals

Structural and upconversion emission properties of Zr O2: Yb3+ - Ho3+ nanocrystals were analyzed as function of Yb3+ concentration. Structural characterization shows a crystallite size up to 80 nm and tetragonal and cubic phase as the main crystalline structures. Strong green (540 nm) and weak red (670 nm) and near infrared (760 nm) emission bands were observed with 968 nm excitation. The upconversion is based on two photons absorption either by the energy transfers from Yb3+ ion or by the excited state absorption. The energy transfer efficiency was calculated to be 50% for 2 mol % of Yb3+ diminishing to less than 20% for higher concentration. The Yb3+ concentration also affects the decay time of the green emission of Ho3+ ion diminishing from 140 ?s for 2 mol % of Yb to 76 ?s for higher concentration. � 2005 American Institute of Physics

Optical And Spectroscopic Characterization Of Er3+-yb 3+co-doped Tellurite Glasses And Fibers

Optical and spectroscopic properties of Er3+-Yb3+ co-doped TeO2-WO3-Nb2O5-Na 2O-Al2O3 glasses and fibers were investigated. Emission spectra and fluorescence lifetimes of 4I13/2 level of Er3+ion as a function of rare earth concentration and fiber length were measured in glasses. Results show that the self-absorption effect broadens the spectral bandwidth of 4I13/2→ 4I15/2 transition and lengthens the lifetime significantly from 3.5 to 4.6 ms. Fibers were fabricated by the rod-in-tube technique using a Heathway drawing tower. The emission power of these Er3+-Yb 3+ co-doped Step Index Tellurite Fibers (SITFs; lengths varying from 2 to 60 cm) were generated by a 980 nm diode laser pump and then the emission power spectra were acquired with an OSA. The maximum emission power spectra, within the 1530-1560 nm region, were observed for fiber lengths ranging from 3 to 6 cm. The highest bandwidth obtained was 108 nm for 8 cm fiber length around 1.53 μm. © 2014 Published by Elsevier B.V.31793101Li, L., Morrell, M., Qiu, T., Temyanko, V.L., Schulzgen, A., Mafi, A., Kouznetsov, D., Peyghambarian, N., (2004) Appl. Phys. Lett., 85, pp. 2721-2723Nilsson, J., Jaskorzynska, B., Blixt, P., (1993) Photonics Technol. Lett., IEEE, 5, pp. 1427-1429Ohishi, Y., Mori, A., Yamada, M., Ono, H., Nishida, Y., Oikawa, K., (1998) Opt. Lett., 23, pp. 274-276Lin, H., Tanabe, S., Lin, L., Yang, D.L., Liu, K., Wong, W.H., Yu, J.Y., Pun, E.Y.B., (2006) Phys. Lett. A, 358, pp. 474-477Udovic, M., Thomas, P., Mirgorodsky, A., Durand, O., Soulis, M., Masson, O., Merle-Méjean, T., Champarnaud-Mesjard, J.C., (2006) J. Solid State Chem., 179, p. 3252Gamulin, O., Ivanda, M., Mitsa, V., Balarin, M., Kosović, M., (2011) Journal of Molecular Structure, 993, pp. 264-268Adam, A.B., (2009) J. King Saud Univ. -Sci., 21, pp. 93-97Mao, A.W., Kaseman, D.C., Youngman, R.E., Aitken, B.G., Sen, S., (2013) J. Non-Cryst. Solids, 375, pp. 40-46Qin, L., Shen, Z.X., Low, B.L., Lee, H.K., Lu, T.J., Dai, Y.S., Tang, S.H., Kuok, M.H., (1997) J. Raman Spectrosc., 28, pp. 495-499Almeida, R.M., Pereira, J.C., Messaddeq, Y., Aegerter, M.A., (1993) J. Non-Cryst. Solids, 161, pp. 105-108Akella, A., Downing, E.A., Hesselink, L., (1997) J. Non-Cryst. Solids, 213-214, p. 1Kumar Singh, A., Mehta, N., Singh, K., (2009) Physica B: Condens. Matter, 404, p. 3470Kato, D., (1973) Appl. Phys. Lett., 22, p. 3Kumar, S., Singh, K., (2012) Thermochim. Acta, 528, p. 32Smektala, F., Matecki, M., (1995) J. Non-Cryst. Solids, 184, p. 314Diniz, R.E.O., Ribeiro, S.J.L., Messaddeq, Y., Ghiselli, G., Nunes, L.A., (1997) J. Non-Cryst. Solids, 219, p. 187Reben, M., Li, H., (2011) Int. J. Applied Glass Science, 2, pp. 96-107Ono, H., Mori, A., Shikano, K., Shimizu, M., (2002) Photonics Technol. Lett., IEEE, 14, p. 1073Mori, A., Ono, H., Shikano, K., Shimizu, M., (2002) Electron. Lett., 38, pp. 1419-1420Zhang, J., Dai, S., Li, S., Xu, S., Wang, G., Hu, L., (2004) Mater. Lett., 58, p. 3532Auzel, F.E., (1973) Proc. IEEE, 61, p. 758Nandi, P., Jose, G., (2008) Opt. Fiber Technol., 14, p. 275Mahdi, M.A., Mahamd Adikan, F.R., Poopalan, P., Selvakennedy, S., Ahmad, H., (2001) Opt. Commun., 187, p. 389Di Muro, R., Lowe, D., Wilson, S., (2001) Photonics Technol. Lett., IEEE, 13, p. 1073Zhang, J., Dai, S., Wang, G., Sun, H., Zhang, L., Hu, L., (2005) J. Lumin., 115, p. 45Dai, S.-X., Zhang, J.-J., Li, S.-G., Xu, S.-Q., Wang, G.-N., Yang, J.-H., Hu, L.-L., (2004) Chin. Phys., 13, p. 2162Dai, S., Xu, T., Nie, Q., Shen, X., Wang, X., (2008) J. Rare Earths, 26, p. 915Nie, Q.H., Wang, X., Xu, T.F., Shen, X., Liu, L., Industrial Informatics, 2006 IEEE International Conference on 2006, pp. 1129-1134Shen, S., Naftaly, M., Jha, A., (2002) Opt. Commun., 205, p. 101Wemple, S.H., (1979) Appl. Opt., 18, p. 31Narro-García, R., Chillcce, E.F., Barbosa, L.C., De Posada, E., Arronte, M., Rodriguez, E., (2013) J. Lumin., 134, p. 528Hruby, A., Czech, J., (1972) Phys B, 22, p. 1187Wang, J.S., Vogel, E.M., Snitzer, E., (1994) Opt. Mater., 3, p. 187Chillcce, E.F., Mazali, I.O., Alves, O.L., Barbosa, L.C., (2011) Opt. Mater., 33, pp. 389-396Raouf, A.H., (2001) Tellurite Glasses Handbook: Physical Properties and Data, Primera, , ed. CRC Press Boca Raton, FloridaDesirena, H., Rosa, E.D.L., Shulzgen, A., Shabet, S., Peyghambarian, N., (2008) J. Phys. D: Appl. Phys., 41, p. 095102Jakutis, J., Gomes, L., Amancio, C.T., Kassab, L.R.P., Martinelli, J.R., Wetter, N.U., (2010) Opt. Mater., 33, p. 107Desirena, H., Rosa, E.D.L., Salas, P., Meza, O., (2011) J. Phys. D: Appl. Phys., 44, p. 45530

Optical and spectroscopic characterization of Er3+-Yb3+ co-doped tellurite glasses and fibers

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPOptical and spectroscopic properties of Er3+-Yb3+ co-doped TeO2-WO3-Nb2O5-Na2O-Al2O3 glasses and fibers were investigated. Emission spectra and fluorescence lifetimes of I-4(13/2) level of Er3+ ion as a function of rare earth concentration and fiber length were measured in glasses. Results show that the self-absorption effect broadens the spectral bandwidth of I-4(13/2)-> I-4(15/2) transition and lengthens the lifetime significantly from 3.5 to 4.6 ms. Fibers, were fabricated by the rod-in-tube technique using a Heathway drawing tower. The emission power of these Er3+-Yb3+ co-doped Step Index Tellurite Fibers (SITFs; lengths varying from 2 to 60 cm) were generated by a 980 nm diode laser pump and then the emission power spectra were acquired with an OSA. The maximum emission power spectra, within the 1530-1560 nm region, were observed for fiber lengths ranging from 3 to 6 cm. The highest bandwidth obtained was 108 nm for 8 cm fiber length around 1.53 um. (C) 2014 Published by Elsevier B.V.Optical and spectroscopic properties of Er3+-Yb3+ co-doped TeO2-WO3-Nb2O5-Na2O-Al2O3 glasses and fibers were investigated. Emission spectra and fluorescence lifetimes of I-4(13/2) level of Er3+ ion as a function of rare earth concentration and fiber length were measured in glasses. Results show that the self-absorption effect broadens the spectral bandwidth of I-4(13/2)-> I-4(15/2) transition and lengthens the lifetime significantly from 3.5 to 4.6 ms. Fibers, were fabricated by the rod-in-tube technique using a Heathway drawing tower. The emission power of these Er3+-Yb3+ co-doped Step Index Tellurite Fibers (SITFs; lengths varying from 2 to 60 cm) were generated by a 980 nm diode laser pump and then the emission power spectra were acquired with an OSA. The maximum emission power spectra, within the 1530-1560 nm region, were observed for fiber lengths ranging from 3 to 6 cm. The highest bandwidth obtained was 108 nm for 8 cm fiber length around 1.53 um.31793101CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONACYT [134111]Sem informaçãoSem informaçãoThe authors would like to thank the Brazilian agencies CNPq, FAPESP and CePOF-UNICAMP and the Mexican agency COFAA for their financial support. In addition, we acknowledge to CONACYT for financial support through grant 134111 and postdoctoral scholarship for R.N.G

Spectroscopic properties of tellurite glasses co-doped with Er3+ and Yb3+

Spectroscopic characterization of Er3+/Yb3+ co-doped tellurite glasses 70.8TeO2-5Al2O3-13K2O-(11-x)-BaO-0.2Er2O3-xYb2O3, where x=0, 0.4, 0.8, 1.2 and 2 mol% has been carried out through X-ray diffraction, Raman, absorption and luminescence spectra. The Judd-Ofelt intensity parameters were calculated for 0.2 mol% Er3+-doped glass and are used to evaluate radiative properties such as transition probabilities, branching ratios and radiative lifetime. The emission cross-section of the 4I13/2→4I15/2 transition has been calculated from the absorption data using McCumber's theory. The emission intensity of both, visible and infrared signals as a function of Yb2O3, have been studied under 980 nm and 375 nm laser excitation. The physical mechanisms responsible for both, visible and infrared signals in the tellurite samples have been explained in terms of the energy transfer and excited state absorption process. The FWHM of the 4I13/2→4I15/2 transition as a function of Yb2O3 mol% and distance (δ) between the laser focusing point and the end-face of the glass has been reported. It was observed both, experimentally and numerically, a change in the FWHM with variations of δ less than 8 mm. The latter was attributed to the radiation trapping effect. © 2015 Elsevier B.V. All rights reserved

Photoluminescence characterization of porous YAG: Yb3+-Er 3+ nanoparticles

Yb3+/Er3+ codoped yttrium aluminium garnet (YAG) porous nanocrystals were prepared by glycolate method assisted with poly-vinyl alcohol (PVA) and urea. The typical cubic structure for YAG was confirmed from XRD with crystallite average size of ~40 nm, calculated from Scherrer formula and corroborated by TEM. Strong green and red upconversion emissions are observed readily with the naked eyes, and the color coordinates were obtained from emission spectra. A theoretical model to calculate CIE coordinate as a function of donor (Yb3+) and acceptors (Er3+) concentration is proposed. The eye-safe near infrared emitted signal and fluorescence lifetime were also measured and results show lifetime as large as 8.5 ms. The maximum energy transfer efficiency from Yb3+ to Er 3+ was 72% for 20 mol% of Yb2O3. The proposed mechanisms for signal emitted are explained in terms of direct and energy back transfer processes, and cross relaxation. � 2014 Elsevier B.V

Spectroscopic properties of Eu3+/Nd3+ co-doped phosphate glasses and opaque glass-ceramics

This paper reports the fabrication and characterization of Eu3+/Nd3+ co-doped phosphate (PNE) glasses and glass-ceramics as a function of Eu3+ concentration. The precursor glasses were prepared by the conventional melt quenching technique and the opaque glass-ceramics were obtained by heating the precursor glasses at 450 °C for 30 h. The structural and optical properties of the glass and glass-ceramics were analyzed by means of X-ray diffraction, Raman spectroscopy, UV-VIS-IR absorption spectroscopy, photoluminescence spectra and lifetimes. The amorphous and crystalline structures of the precursor glass and opaque glass-ceramic were confirmed by X-ray diffraction respectively. The Raman spectra showed that the maximum phonon energy decreased from 1317 cm-1 to 1277 cm-1 with the thermal treatment. The luminescence spectra of the glass and glass-ceramic samples were studied under 396 nm and 806 nm excitation. The emission intensity of the bands observed in opaque glass-ceramic is stronger than that of the precursor glass. The luminescence spectra show strong dependence on the Eu3+ ion concentration in the Nd3+ ion photoluminescence (PL) intensity, which suggest the presence of energy transfer (ET) and cross-relaxation (CR) processes. The lifetimes of the 4F3/2 state of Nd3+ ion in Eu3+/Nd3+ co-doped phosphate glasses and glass-ceramics under 806 nm excitation were measured. It was observed that the lifetimes of the 4F3/2 level of Nd3+ of both glasses and glass-ceramics decrease with the increasing Eu3+ concentration. However in the case of opaque glass-ceramics the lifetimes decrease only 16%. © 2015 Elsevier B.V. All rights reserved